The great majority of currently known vibrating mass gyros work by exciting a mode of vibration of the vibrating mass in one direction and detecting the vibrations induced in an orthogonal direction by the Coriolis force. They take multiple forms that are designed more and more often with a view to production of so-called MEMs (MicroElectroMechanical systems). These are the least expensive rate of rotation sensors but they suffer from a lack of medium- and long-term stability inherent in their principle of operation, preventing their use, without frequent readjustments, in medium- and long-term navigation applications.